daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: mysqld got signal 11;
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: This could be because you hit a bug. It is also possible that this binary
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: or one of the libraries it was linked against is corrupt, improperly built,
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: or misconfigured. This error can also be caused by malfunctioning hardware.
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: We will try our best to scrape up some info that will hopefully help diagnose
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: the problem, but since we have already crashed, something is definitely wrong
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: and this may fail.
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: 
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: key_buffer_size=16777216
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: read_buffer_size=131072
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: max_used_connections=26
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: max_connections=100
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: threads_connected=14
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: It is possible that mysqld could use up to 
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: key_buffer_size + (read_buffer_size + sort_buffer_size)*max_connections = 233983 K
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: bytes of memory
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: Hope that's ok; if not, decrease some variables in the equation.
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: 
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: thd=0x8bcd3d8
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: Attempting backtrace. You can use the following information to find out
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: where mysqld died. If you see no messages after this, something went
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: terribly wrong...
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: Cannot determine thread, fp=0xb0eb302c, backtrace may not be correct.
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: Stack range sanity check OK, backtrace follows:
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: 0x8193904
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: 0xffffe420
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: 0x8f4af08
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: 0x81ab87b
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: 0x81ff7a0
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: 0x81fe56a
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: 0x81a6fa8
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: 0x81a5b4d
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: 0x81a4fb2
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: 0xb7f9bb63
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: 0xb7e1318a
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: New value of fp=(nil) failed sanity check, terminating stack trace!
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: Please read http://dev.mysql.com/doc/mysql/en/Using_stack_trace.html and follow instructions on how to resolve the stack trace. Resolved
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: stack trace is much more helpful in diagnosing the problem, so please do 
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: resolve it
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: Trying to get some variables.
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: Some pointers may be invalid and cause the dump to abort...
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: thd->query at 0x8cd3eb8 = DELETE FROM share_network  USING share_network,        (friends AS f         RIGHT JOIN share_network AS s         ON f.owner_username=s.username AND            f.username=s.shares_with)  WHERE share_network.username=s.username AND        share_network.shares_with=s.shares_with AND        f.owner_username IS NULL
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: thd->thread_id=66
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: The manual page at http://www.mysql.com/doc/en/Crashing.html contains
daemon.log.5:Aug 17 16:23:18 uk2-host2 mysqld[29965]: information that should help you find out what is causing the crash.